Recently, demands for a high-resolution and high-quality video such as a high definition (HD) video and an ultra high definition (UHD) video have increased in various fields of applications. As a video has higher resolution and higher quality, an amount of information or an amount of bits to be transmitted increases more and more relatively to existing videos. Accordingly, when video information is transferred using media such as existing wired or wireless broadband lines or video information is stored in existing storage media, the information transfer cost and the information storage cost increase. High-efficiency video compressing techniques can be used to solve these problems.
Various techniques such as an inter prediction technique of predicting pixel values of a current picture with reference to pictures previous and/or subsequent to the current picture, an intra prediction technique of predicting pixel values of a current picture using pixel information in the current picture, and an entropy coding technique of allocating a short code to a value of a low appearance frequency and allocating a long code of a value of a high appearance frequency are known as the video compressing techniques. It is possible to effectively compress, transfer, or store video data using such video compressing techniques.